An explosion ripped through a ball-bearing factory in southern New Hampshire on Monday, leaving at least 15 people hurt, a hospital spokesman said.

Authorities dispatched at least eight ambulances and two medical helicopters to the New Hampshire Ball Bearings plant outside Peterborough after the Monday afternoon blast, Assistant Town Administrator Nicole MacStay said.

Monadnock Community Hospital saw 15 patients after the explosion, spokesman Phil McFarland said. Thirteen of those were treated and released, while two were transferred to other hospitals, McFarland said.

Company spokeswoman Kathy Gerrity told CNN none of the injuries appeared to be life-threatening "as far as we know." About 450 people would have been working at the plant at the time of the 3:30 p.m. explosion, Gerrity said.

The factory makes bearing assemblies for aircraft, medical and high-technology industries. New Hampshire Gov. Maggie Hassan said the state has offered to provide "any assistance needed to local first responders."

"My thoughts and prayers go out to those injured in today's explosion, to their families and loved ones, and to the entire Peterborough area where NH Ball Bearings is such an important member of the community," Hassan said in a written statement.